Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A generalized quantum chemical approach for nano- and bio-electronics
KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
2005 (English)Licentiate thesis, comprehensive summary (Other scientific)
Abstract [en]

A generalized quantum chemical approach for electron transport in molecular devices is developed. It allows to treat the devices where the metal electrodes and the molecule are either chemically or physically bonded on equal footing. Effects of molecular length and hydrogen bonding on the current-voltage (I-V) characteristics of molecular devices are discussed. An extension to include the vibration motions of the molecule has been derived and implemented. It provides the inelastic electron tunneling spectroscopy (IETS) of molecular devices with unprecedented accuracy, and reveals important information about the molecular structures that are not accessible in the experiment. The IETS is shown to be a powerful characterization tool for molecular devices.

An effective elongation method has been developed to study the electron transport in nanoand bio-electronic devices at hybrid density functional theory level. It enables to study electronic structures and transportation properties of a 40 nm long self-assembled conjugated polymer junction, a 21 nm long single-walled carbon nanotubes (SWCNT), and a 60 basepairs DNA molecule. It is the first time that systems consisting of more than 10,000 electrons have been described at such a sophisticated level. The calculations have shown that the electron transport in sub-22 nm long SWCNT and short DNA molecules is dominated by the coherent scattering through the delocalized unoccupied states. The derived length dependence of coherent electron transport in these nanostructured systems will be useful for the future experiments. Moreover, some unexpected behaviors of these devices have been discovered.

Place, publisher, year, edition, pages
Stockholm: KTH , 2005. , 48 p.
Keyword [en]
Biotechnology
Keyword [sv]
Bioteknik
National Category
Industrial Biotechnology
Identifiers
URN: urn:nbn:se:kth:diva-286ISBN: 91-7178-022-X (print)OAI: oai:DiVA.org:kth-286DiVA: diva2:8586
Presentation
2005-05-24, Sal FB53, AlbaNova, 10:00
Opponent
Supervisors
Note
QC 20101203Available from: 2005-07-06 Created: 2005-07-06 Last updated: 2011-11-23Bibliographically approved
List of papers
1. Length dependence of coherent electron transportation in metal-alkanedithiol-metal and metal-alkanemonothiol-metal junctions
Open this publication in new window or tab >>Length dependence of coherent electron transportation in metal-alkanedithiol-metal and metal-alkanemonothiol-metal junctions
2004 (English)In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 400, no 4-6, 336-340 p.Article in journal (Refereed) Published
Abstract [en]

We have applied the elastic-scattering Green's function theory to study the coherent electron transportation processes in both metal-alkanedithiol-metal (gold-[S(CH2)(n)S]-gold, n = 8-14) and metal-alkanemonothiol-metal (gold-[H(CH2)(n)S]-gold, n = 814) at the hybrid density functional theory level. It is shown that the current decreases exponentially with the molecular length. At the low temperature limit the electron decay rate, beta, for alkanedithiol junction is found to be around 0.30/CH2 at 1.0 V bias, much smaller than the calculated value of 0.60/CH2 for alkanemonothiol junction. The decay rate for alkanedithiol junction at the room temperature is neither sensitive to the activation of the Au-S stretching vibrational mode nor to the external bias. The calculated current-voltage characteristics and decay rates for both junctions are in excellent agreement with the corresponding experimental results.

Keyword
alkane derivative; dithiol derivative; article; density functional theory; elasticity; electron transport; low temperature; molecular dynamics; room temperature
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-6985 (URN)10.1016/j.cplett.2004.10.136 (DOI)000225906300012 ()2-s2.0-10344228738 (Scopus ID)
Note
QC 20100730Available from: 2007-04-17 Created: 2007-04-17 Last updated: 2017-12-14Bibliographically approved
2. First-principles simulations of inelastic electron tunneling spectroscopy of molecular electronic devices
Open this publication in new window or tab >>First-principles simulations of inelastic electron tunneling spectroscopy of molecular electronic devices
2005 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 5, no 8, 1551-1555 p.Article in journal (Refereed) Published
Abstract [en]

Inelastic electron tunneling spectroscopy (IETS) is a powerful experimental tool for studying the molecular and metal contact geometries in molecular electronic devices. A first-principles computational method based on the hybrid density functional theory is developed to simulate the IETS of realistic molecular electronic devices. The calculated spectra of a real device with an octanedithiolate embedded between two gold contacts are in excellent agreement with recent experimental results. Strong temperature dependence of the experimental IETS spectra is also reproduced. It is shown that the IETS is extremely sensitive to the intramolecular conformation and the molecule-metal contact geometry changes. With the help of theoretical calculations, it has finally become possible to fully understand and assign the complicated experimental IETS and, more importantly, provide the structural information of the molecular electronic devices.

Keyword
Computer simulation; Electron tunneling; Probability density function; Spectroscopy; Thermal effects; Inelastic electron tunneling spectroscopy (IETS); Intramolecular conformations; Molecular electronic devices; Structural information; article; chemical model; chemistry; computer simulation; electronics; equipment; evaluation; feasibility study; materials testing; methodology; scanning tunneling microscopy; spectroscopy; Computer Simulation; Electronics; Equipment Failure Analysis; Feasibility Studies; Materials Testing; Microscopy, Scanning Tunneling; Models, Chemical; Nanostructures; Spectrum Analysis
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-6988 (URN)10.1021/nl050789h (DOI)000231211300005 ()2-s2.0-24344435119 (Scopus ID)
Note
QC 20100730. Titeln ändrad från "First-principles simulations of inelastic electron tunneling spectroscopy of molecular junctions"Available from: 2007-04-17 Created: 2007-04-17 Last updated: 2017-12-14Bibliographically approved
3. Electron transport in self-assembled polymer molecular junctions
Open this publication in new window or tab >>Electron transport in self-assembled polymer molecular junctions
Show others...
2006 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 96, no 2, 027801- p.Article in journal (Refereed) Published
Abstract [en]

A molecular junction of a poly(p-phenyleneethynylene)s derivative with thioacetate end groups (TA-PPE) was fabricated by self-assembling. Nanogap electrodes made by electroplating technique was used to couple thiol end groups of TA-PPE molecules. Room temperature current-voltage characteristics of the molecular junction exhibited highly periodic, repeatable, and identical stepwise features. First-principles calculations suggest that one possibility for the equidistant step is due to the opening of different conducting channels that corresponds to the unoccupied molecular orbitals of the polymer in the junction. It is interesting to see that an 18 nm long polymer is of quantized electronic structures and behaves like a quantum transport device.

Keyword
Electrodes; Electroplating; Molecular dynamics; Nanostructured materials; Polymers; Self assembly; Current-voltage; Molecular junction; Quantized electronic structures; Thioacetate end groups (TA-PPE); Electron transport properties
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-6986 (URN)10.1103/PhysRevLett.96.027801 (DOI)000234758100098 ()2-s2.0-32644481386 (Scopus ID)
Note
QC 20100730. Titeln ändrad från "Coherent electron transport in self-assembled conjugated polymer molecular junctions".Available from: 2007-04-17 Created: 2007-04-17 Last updated: 2017-12-14Bibliographically approved
4. Effects of Hydrogen Bonding on Current−Voltage Characteristics of Molecular Junctions
Open this publication in new window or tab >>Effects of Hydrogen Bonding on Current−Voltage Characteristics of Molecular Junctions
2006 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 125, no 19, 194703-1-194703-7 p.Article in journal (Refereed) Published
Abstract [en]

We present a first-principles study of hydrogen bonding effect on current-voltage characteristics of molecular junctions. Three model charge-transfer molecules, 2'-amino-4,4'-di(ethynylphenyl)-1-benzenethiolate (DEPBT-D), 4,4'-di(ethynylphenyl)-2'-nitro-1-benzenethiolate (DEPBT-A), and 2'-amino-4,4'-di(ethynylphenyl)-5'-nitro-1-benzenethiolate (DEPBT-DA), have been examined and compared with the corresponding hydrogen bonded complexes formed with different water molecules. Large differences in current-voltage characteristics are observed for DEPBT-D and DEPBT-A molecules with or without hydrogen bonded waters, while relatively small differences are found for DEPBT-DA. It is predicted that the presence of water clusters can drastically reduce the conductivities of the charge-transfer molecules. The underlying microscopic mechanism has been discussed.

Keyword
Charge transfer, Current voltage characteristics, Electric conductivity, Hydrogen bonds;, Mathematical models, Water, Charge transfer molecules, Molecular junctions, Aromatic compounds
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:kth:diva-7524 (URN)10.1063/1.2364494 (DOI)000242181800066 ()2-s2.0-33845301692 (Scopus ID)
Note
QC 20100804Available from: 2007-09-28 Created: 2007-09-28 Last updated: 2017-12-14Bibliographically approved
5. First-Principles Study of Electron Transport in Single-Walled Carbon Nanotubesthat are 2 to 22 nm in Length.
Open this publication in new window or tab >>First-Principles Study of Electron Transport in Single-Walled Carbon Nanotubesthat are 2 to 22 nm in Length.
(English)Article in journal (Other academic) Submitted
National Category
Industrial Biotechnology
Identifiers
urn:nbn:se:kth:diva-27007 (URN)
Note
QS 20120327Available from: 2010-12-03 Created: 2010-12-03 Last updated: 2012-03-27Bibliographically approved
6. Coherent Electron Transport in DNA Molecules
Open this publication in new window or tab >>Coherent Electron Transport in DNA Molecules
(English)Manuscript (preprint) (Other academic)
National Category
Industrial Biotechnology
Identifiers
urn:nbn:se:kth:diva-27008 (URN)
Note
QC 20101203Available from: 2010-12-03 Created: 2010-12-03 Last updated: 2010-12-03Bibliographically approved

Open Access in DiVA

fulltext(2840 kB)1075 downloads
File information
File name FULLTEXT01.pdfFile size 2840 kBChecksum MD5
3e926141e0681ca4d4e845cd4ae123c12f40a990f896ede065fe24745da584e3c35eef8d
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Jiang, Jun
By organisation
Theoretical Chemistry (closed 20110512)
Industrial Biotechnology

Search outside of DiVA

GoogleGoogle Scholar
Total: 1075 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 745 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf